An electric motorcycle or electric bicycle mounted with a large battery uses a control module for monitoring the voltage and temperature of the battery. A washing machine or the like also uses a current control module. These control modules are required to be water-resistant because of the supposition of water splashing on them. To this end, a printed circuit board of control module in a known structure is sealed with a resin (filler).
In these control modules, a control board mounted with conducting members and electronic components is disposed in an electrically insulating case, which is injected and hardened with a liquid filler. The filler is water-resistant and electrically insulating. To prevent voids, the injection and hardening of the filler is performed under reduced pressure in a decompression chamber. A failure occurs if aluminum electric field capacitors for use as the electronic components are kept under reduced pressure, because of their nature. Thus, the filler must be injected and hardened under normal pressure.
In the control module manufacturing method, the amount of filler used for sealing is determined in accordance with the size of large-sized electronic components so as to cover all electronic components with resin, and the filler for sealing must be fully injected to reach the edge of the case. Possibly, therefore, the filler may overflow the case during delivery to a subsequent process or the like. Since the filler must be injected into regions where sealing is not required, i.e., into regions located above small-sized components, weight reduction is inhibited and the high material cost becomes a problem.
An object of the present embodiment is to provide a control module manufacturing method in which the amount of resin used can be reduced and delivery to a subsequent process can be facilitated.